Thermoplastic resins can have improved properties such as lower specific gravity as compared to glass or metal and also can have improved formability, impact resistance, and the like. Recently, thermoplastic resins have been used to manufacture plastic products, such as electric/electronic products, to meet demands for less expensive and larger and lighter products. The plastic products have rapidly replaced conventional glass or metal products and been widely used from electric/electronic products to automobile parts.
For example, an ASA resin consisting of an acrylate-styrene-acrylonitrile copolymer has excellent stability upon exposure to ultraviolet (UV) rays and thus, has been widely used for products that are directly exposed to UV rays, such as exterior components of a car, building materials, and the like. However, the ASA resin necessarily requires excessive addition of an acrylate-based rubber due to low impact-resistance characteristics of the rubber and thus, has a problem of heat resistance deterioration, which limits its use. For example, a radiator grill, an outside mirror housing, or the like as an exterior component for a car manufactured using the ASA resin may be distorted due to an excessive amount of rubber added to the ASA resin after injection-molding the products and frequently damaged by a chip flying during driving.
In order to solve this problem, the ASA resin may be alloyed with a polycarbonate (PC) resin having high impact strength and heat resistance. The alloy, however, may not realize excellent coloring properties due to the difference between the high refractive index of the PC resin and the low refractive index of the ASA resin. Various patents about the ASA resin, for example, Korean Patent Laid-Open No. 2009-0038507 and the like have been issued, but there is no patent about improvement of coloring properties of the alloy composition of the PC resin and the ASA resin. Accordingly, there is a need for a thermoplastic resin composition having excellent impact strength, heat resistance, weather resistance and coloring properties and a molded article using the same.